The present invention relates generally to series progressive divider valves. More particularly, the present invention relates to fittings for plugging outlet ports such that fluid can be directed to the next outlet port in the series progression.
Series progressive divider valves have long-existed in the art and comprise a mechanism for dividing a single, steady input of pressurized fluid into multiple, distributed bursts of fluid. Thus, fluid is delivered to the valve body at a single inlet port and delivered to multiple discrete outlet ports through cyclic operation of an array of pistons or spools under pressure from the fluid. The valve output cycles continuously through the outlet ports in a scheduled progression based on movement of the array of pistons. For example, conventional series progressive divider valves include an array of pistons in which the central axes of all the pistons are arranged in a single plane. Outlets for each end of the piston are typically arranged in a plane parallel to the plane of the pistons. The outlets are connected to the pistons through an elaborate system of portings machined into the valve body.
The pistons reciprocate within bores of the valve body enclosed by end caps. The pistons themselves include a pair of axially spaced undercuts such that each piston forms three lobes. As such, when a piston is inserted into a bore and enclosed by end caps, four pressure chambers are formed: one end chamber at each end of the piston and two internal chambers within the piston. Each end chamber is connected to an internal chamber of the next piston in the progression through porting extending through the valve body. Additionally, each internal chamber is connected to an outlet of the valve through the use of separate porting. Thus, a four piston valve includes eight outlets. High pressure inlet porting connects each piston bore and, depending on the position of each piston, one of the internal chambers for each piston. All connections and outlets are made on the same side of the valve body and at the same ends of the pistons, except, however, end chambers of a “first” piston are connected to internal chambers of a “last” piston such that the pistons can reverse direction and the series progression can continue ad infinitum.
Operation of a typical series progressive divider valve is explained with reference to drawings from the prior art, specifically U.S. Pat. No. 4,312,425 to Snow et al., which shows a simplified piston and outlet configuration. FIG. 1 shows a perspective view of a typical series progressive divider valve having valve body 10 formed from a plurality of block bodies 10A-10H. FIG. 2 shows a schematic of valve body 10 including pistons 12A, 12B and 12C. FIG. 1 and FIG. 2 are discussed concurrently. As shown, each of pistons 12A-12C includes three lobes, designated as 14A, 14B, 14C, 16A, 16B, 16C, 18A, 18B and 18C, respectively. Lobes 14A-18C produce undercuts 20A, 20B, 20C, 22A, 22B and 22C, respectively. Pistons 12A, 12B and 12C reciprocate in bores 24A, 24B and 24C, respectively, which form end chambers 26A, 26B, 26C, 28A, 28B and 28C, respectively. Additionally, undercuts 20A-22C form internal chambers 30A, 30B, 30C, 32A, 32B and 32C. Each of undercuts 20A-22C, and the chamber formed thereby, is fluidly connected to one of valve outlets 38A-38F and another undercut via porting machined into valve body 10. Specifically, internal pumping chamber 30A is fluidly connected to end chamber 28C via porting 36A and to outlet 38A via porting 40A. Internal pumping chamber 30B is fluidly connected to end chamber 26A via porting 36B and to outlet 38B via porting 40B. Internal pumping chamber 30C is fluidly connected to end chamber 26B via porting 36C and to outlet 38C via porting 40C. Internal pumping chamber 32A is fluidly connected to end chamber 26C via porting 36D and to outlet 38D via porting 40D. Internal pumping chamber 32B is fluidly connected to end chamber 28A via porting 36E and to outlet 38E via porting 40E. Internal pumping chamber 32C is fluidly connected to end chamber 28B via porting 36F and to outlet 38F via porting 40F.
High pressure porting 42 distributes high pressure fluid from inlet 44 to bores 24A-24C. High pressure porting 42 fluidly connects inlet 44 to internal chambers 30A-32C, depending on the position of lobes 16A-16C. High pressure fluid is always provided directly to one side of each of lobes 16A-16C depending on the position of each of pistons 12A-12C. As shown, high pressure fluid is provided to internal chambers 32A, 30B and 30C. As such, high pressure fluid is also provided to end chambers 26C, 26A and 26B, via porting 36D, 36B, 36C, respectively. In the last piston movement before the configuration shown in FIG. 2, low pressure fluid has been dispensed from port 38F via movement of piston 12B downward through porting 36F and 40F. Subsequently, as shown in FIG. 2, high pressure fluid is provided to chambers 26B and 26C. High pressure fluid in chambers 26B and 26C does not produce movement of pistons 12B and 12C because lobes 18B and 18C are already engaged with the end caps of bores 24B and 24C. High pressure fluid in chamber 26A will, however, produce downward movement of piston 12A as end chamber 28A discharges low pressure fluid. Low pressure fluid in end chamber 28A, through porting 36E, displaces fluid in internal chamber 32B out of outlet 38E through porting 40E.
Such displacement of pistons 12A-12C is repeated so long as high pressure fluid is provided to inlet 44, with porting 36D and 36A connecting internal chambers and end chambers on opposite ends of the pistons to permit reversing of the axial piston positions. For example, piston 12C moves downward pushing fluid through outlet 38A, piston 12B then moves downward pushing fluid through outlet 38F, piston 12A then moves downward pushing fluid through outlet 38E, then piston 12C moves upward pushing fluid through outlet 38D, then piston 12B moves upward pushing fluid through outlet 38C and finally piston 12A moves upward pushing fluid through outlet 38B.
As mentioned, in order to achieve such cyclic movement, valve body 10 is provided with an elaborate system of three dimensional porting. Such porting is produced using a series of machining operations, particularly drilling, in a plurality of rectangular blocks. For example, valve body 10 is produced from blocks 10A-10H as shown in FIG. 1. Blocks 10A and 10E comprise “inlet” and “end” blocks with porting necessary to route fluid between pistons at the end of the array. Intermediate blocks 10B-10D are identical to each other and include piston bores 24A-24C. Intermediate blocks 10F-10H are identical to each other and include outlets 38A-38F. Intermediate blocks 10B-10D are paired with intermediate blocks 10F-10H to form a piston and outlet combination. In order to change the number of pistons and outlet ports one pair of intermediate blocks can be removed. However, such an operation requires tedious and time consuming disassembly and reassembly of the blocks, such as by removal and replacement of screws 46A-46I. Such assembly intricacies are further detailed are described in the aforementioned U.S. Pat. No. 4,312,425 to Snow et al.
The use of a plurality of separate intermediate blocks reduces or eliminates the need for unnecessary “open ended” drilling operations. These drilling operations are intended to connect other passages, but are not intended to produce a passage that opens to the exterior of the valve body. However, due to manufacturing limitations the drilling operations are necessary and the open end must be plugged. For example, two parallel ports may need to be connected by drilling a perpendicular port. The perpendicular port does not, however, need to be opened to the exterior of the valve block. Such ports have typically been closed off using steel balls welded in place, as is described in U.S. Pat. No. 3,467,222 to Gruber. These methods thus require additional manufacturing steps and additionally introduce potential leak points and stress points into the system.
In other configurations of prior art series progressive valves, outlet ports 38A-38F can be connected to each other through cross-porting and plugging. In particular, outlet 36C can be ported to connect with outlets 38A and 38B. Likewise, outlet 38F can be ported to connect with outlets 38E and 38D. When configured as such, outlet 38B can be plugged to direct what would be its discharge into outlet 38C so that outlet 38C will receive a double shot of fluid. Additionally, outlet 38C can be plugged so outlet 38A can be configured to receive a triple shot of fluid. However, in conventional series progressive valves using intermediate blocks, outlet 38A cannot be plugged because no porting is provided between outlets 38A and 38B due to the complexity of the required porting that cannot be introduced into the modular block design of blocks 10A-10H. In other words, the required porting would result in each intermediate block having a unique configuration. As such, outlet 38A becomes a “last stop” outlet that must be permitted to allow fluid from valve body 10 because there is not another outlet to which fluid can be routed. As such if outlets 38A, 38B and 38C were plugged, operation of valve body 10 would seize up. Outlet 38D also becomes a “last stop” outlet for the same reason.
Cross-porting requires blocking of outlet ports with fittings or plugs from which it is desired to prevent fluid flow. Such cross-port fittings are shown in the Quicklub® Progressive Divider Valves brochure for SSV & SSVM Series valves commercially available from Lincoln Industrial, an SKF company. These fittings, however, require the use of several different plug and ferrule combinations. Other methods of output combining involve force fitting brass plugs into the outlets. These plugs, however, wear after repeated use and become ineffective.